Comments and Diagnosis. This species is easily recognized by the shorter clypeus, with length and width subequal ( Fig. 10View FIGURES 7–12. 7). The clypeus is slightly emarginate, without carinae in the apical portion. This diagnostic feature is unique among the species of Stenosigma —in all other species the clypeus is longer than wide (compare Fig. 10View FIGURES 7–12. 7 with Figs. 8, 9, 11–14View FIGURES 7–12. 7View FIGURES 13–18. 13, 14). We have observed this condition in specimens of both sexes, unlike Giordani Soika (1990) who presented this character as unique to males in his identification key (Giordani Soika, 1990, p. 148). Unfortunately, the holotype is damaged, but the head has been preserved and can be seen in frontal view, allowing observation of the diagnostic character for this species, namely the shorter clypeus.